It is conventional in controlling rotary shafts, such as the shaft of ranges and the like, to provide a control knob adapted to be secured to the projecting end of the control shaft forwardly of the outer wall of the range. Such control knobs utilize hub details which make the control knobs relatively expensive.
Such knobs are conventionally associated with dials for indicating to the user the disposition of the rotary shaft. It is necessary to maintain a relatively low temperature of the knob to permit the user to manipulate the shaft without injury. In one conventional range structure, the control shaft projects forwardly through a small opening in the range wall. The shaft is rotatable and axially movable. Conventionally, the shaft must be urged axially inwardly before rotation of the shaft may be effected, thereby to prevent inadvertent rotation of the shaft.
A number of different rotary control devices are disclosed in prior art patents, including U.S. Pat. No. 783,210 of Roland C. Lewis. The Lewis patent discloses a dial and knob structure for use with permutation locks wherein a dial 6 is removably associated with a hub 4 and a knob 10 by interlocking serrations.
Henry J. Kasch shows, in U.S. Pat. No. 1,563,635 a knob and dial assembly wherein the knob 2 is connected to the dial 1 by a fitted hub element 10.
In U.S. Pat. No. 1,629,891, Louis E. Shaw shows a radiodial wherein the metal hub element 21 is secured to the knob portion of the dial in a boss 20 thereof. The knob portion is formed integrally with the dial portion 17.
In U.S. Pat. No. 2,201,540 of Walter L. Kauffman, II, a pressure control knob is provided wherein a shaft extends through the two-piece hub and knob structure and is provided at its distal end with a dial portion 21 exposed outwardly of the knob.